Machine for the magnetomotive forming of metallic objects

ABSTRACT

A machine for the magnetomotive forming of metallic objects includes a die composed of a plurality of die sections, adjacent die sections being articulated together about a joining line on the inner surfaces thereof, said inner surfaces and joining line of each pair of articulated die sections being coated with a layer of flexible material, e.g. a rubber of 65* Shore hardness, which can carry or transmit an intaglio or cameo image. Means are provided for moving the die sections apart and together about a magnetomotive induction coil.

States Patent [1 1 [111 3,810,373 Queyroix May 14, 1974 [54] MACHINE FOR THE MAGNETOMO'I IVE 3,455,140 7/l969 Galan m1. 72/465 FORMING 0 METALLIC OBJECTS 3,359,835 12/1967 McDowell 76/107 R 585,821 7/1897 Kent 72/478 [75] Inventor: Christian A. Queyroix, Faramans,

France Primary Examiner-Richard J. Herbst [73] Assi nee: Aluminium Suisse S.A., Chippis, Attorney, Agent, or Firm-Robert E. Burns; Emman- Switzerland uel J. Lobato [22] Filed: Dec. 6, 1972 21 App]. No.: 312,705 [57] ABSTRACT A machine for the magnetomotive forming of metallic 30 Foreign Application priority Data objects includes a die composed of a plurality of die Dec 17 I971 France 71018538 sections, adjacent die sections being articulated t0- gether about a joining line on the inner surfaces thereof, said inner surfaces and joining line of each p of articulated die Sections being Coated with a [58] Field 478 107 R layer of flexible material, e.g. a rubber of 65 Shore hardness, which can carry or transmit an intaglio or 56] Refrencs Cited cameo image. Means are provided for moving the die sections apart and together about a magnetomotive UNITED STATES PATENTS induction 3,351,034 ll/l967 Grek .f. 1l3/l20 N 3,507,034 4/1970 Schwinghamer et al 72/56 8 Claims, 3 Drawing Figures PATENTED Y 14 i 153.810.2373

ma 1 a; 2

The invention relates to the magnetomotive forming of metal objects.

For magnetomotively bulging generally cylindrical objects such as cans, a coil is placed inside the object which is itself placed in a die. An electric discharge to the coil,of the order of several kJ, induces a current to flow in the object in a direction opposite to that in the coil. The magnetic field associated with the induced current reacts against the magnetic field associated with the coil current thus subjecting the object to a very high outwardly directed force so that the object yields and is outwardly compressed against the die. Imprints on the die are thus impressed onto the object. In order to avoid energy losses due to induction in the die, the die is generally provided in a synthetic insulating materiaL- To enable removal of the formed generally cylindrical object, split dies including a plurality of die sections .are usually'employed, and the object is removed as in dressing operations in conventional die casting. This, however, may involve difficulties when the die has imprints which terminate in the proximity ofa joint between sections of the split die, which difficulty is met in dressingoperations in general.

The invention proposes a simple and inexpensive solution to this problem in the case ofa die formagnetomotive forming. I

According to the invention, a machine for the mag netomotive forming of metallic objects includes a die composed of a plurality of die sections, pairs of adjacent die sections being articulated together about a joining line on the inner surfaces thereof, amagnetomotive induction coil, and means for moving said die sections apart and together about said coil, the inner 2 The means for moving the die sections apart and together can include, for each pair of articulated die sec tions, a pin fixed to each die section and protruding from an outer surface thereof, a traction spring joining the pins of the two die sections of each pair, said spring tending to pivotally open out said sections, a bearing piece adapted to bear against the outer surfaces of the two die sections of each pair, and means for moving the bearing pieces of said pairs of die sections in synchronization either away from or towards a central axis of the die, said bearing pieces being adapted during movement thereof towards the die axis, when part of said flexible layer over the joining lines of pairs of die sections comes to bear against an object placed in the die and about said coil, to pivotally close together the die sections of each pair against the action of said springs.

ing two pairs of articulated die sections 4, 5 and 6, 7 the I upper sections 4, 5 being carried by an upper support 8, and the lower sections 6, 7 being carried by a lower support 9. The machine is symmetrical about the vertical plane X-X, so that the following description is confined to the lefthand part of the machine. The dies and their supports are also symmetrical about the horizontal plane YY, which corresponds to the plane of surfaces and said joining line of each pair of articulated die sections being coated with a layer of flexible material.

The flexible layer, which may have a thickness of sev- I eral millimetres, allows separation of the. die sections by a pivotal movement of the-articulated pairs of sections in a manner to facilitate removal of the magnetomotively formed object from the die. The flexible layer also allows a very tight fit between the object to be formed and the die.

The machine may include at least two pairs of articulated die sections, said means for moving said die sections apart and together including means for simultaneously moving each pair of articulated die sections away from or towards a central axis of the die to open or close the die respectively, means for pivotally opening out the two diesections of each pair during opening of the die, and means for pivotally closing up the two die sections of each pair during closing of the die. I

When said die includes at least three die sections, the inner surfaces and joining lines of the adjacent pairs of die sections can be coated with a single continuous layer of flexible material extending from one extreme edge of one end die section to another extreme edge of another end die section, which extreme edges meet together in a closed position of the die, said means for moving said die sections apart and together including means for pivotally moving each adjacent pair of die sections about their joining line.

joining of the opposed pairs of sections of the dies, as well as being symmetrical about the vertical plane ZZ. In FIG. 2, the sections 4 and 5 are shown in the closed position of the die, while the, sections 6 and 7 are shown in the open position of the die. This representation is of course given solely for the purpose of explanation, since in operation all of the die sections are open or closed simultaneously.

The centre of the dies receive induction coils 10 through which a battery of capacitors,,not shown, may be discharged, this technique being known per se. The induction coils can, for example, be supported by a known type of unit carrying the battery of capacitors.

The upper support 8 carries three curved plates 11 defining cylindrical surfaces whose axes coincide, when the dies are in the closed position, with the axes of the respective dies-The lower support 9 is provided with analogous plates 12. The plates 11 and 12 each include oblong holes 13,14, and 13,14 respectively, through which holes pins 15 and 16 engage. As shown for the upper pins 15,16, these pins are screwed in the respective sections 4 and 5 and have cylindrical parts 15a, 16a respectively which pass through holesl3, 14, in the plates 11. These holes are disposed along the central plane Z-Z and are symmetrical about the plane of articulation of the sections 4,5 and 6,7. Adjacent to the outer faces of plates 11, said parts 15a, 16a carry stopforming flanges 15b, 16b respectively. The outer ends of pins and 16 are connected by a traction spring 17.

The inside of each pair of articulated die section is covered with a continuous layer l8, 19 respectively of a flexible material, which forms a flexible articulation between each pair of sections. The material of these layers, for example a rubber of 65 Shore hardness, is able to carry or transmit an intaglio or cameo image. The die sections are provided for example in Technyl (Registered Trade Mark) nylon.

The supports 8 and 9, which can move apart from one another and towards one another, are held in position and guided in relation to one another by four vertical guide rods 20. The support 9 is additionally guided in vertical slideways 21 fixed to a frame 22'.

To each of the ends of supports 8 and 9 are attached two pairs of arms 22, 23. The other ends of each pair of arms 22 and 23 are pivotally mounted to a head 24 of a piston 25 slidably mounted in two bearings 26 and 27 and driven by a cross-bar 28 the middle of which is fixed to the end ofa piston 29 ofa pneumatic jack 30. An identical jack is provided at the right hand end of the machine for actuation of a piston analogous to piston 25. The two jacks have a common supply in a manner such that their movements are exactly synchronized. In FIG. 1 and in full lines in FIG. 2, the piston 25 is shown in a position corresponding to the closed position of the dies. In the open position, the piston 25 moves inwards to bring head 24 to position 24', as indicated in broken lines in FIG. 2, thus bringing the pairs of arms into a vertical position, as shown for arm 23 in FIG. 2.

Operation of the described machine is as follows:

With the dies open, i.e., in the position shown for support 9 in FIG. 2, the piston head 24 is in position 24', and the sections 6 and 7 are held opened out relative to one another by means of spring 17, pivotal opening of the sections being limited on the one hand by the ends of the oblong holes 13 and 14' against which pins 15' and 16' abut and, on the other hand, by contact of the sections 6 and 7 at 31. Although the spring 17 tends to further pivot the pins 15' and 16 about their points of contact against the ends of holes 13' and 14', and thus separate the sections 6 and 7, such separation is prevented by the layer 19. With all ofthe die sections in this open position, an object to be formed, for example a cylindrical aluminium blank (not shown) for forming a can, is introduced about the coil 10 by means not shown. After introduction of the object, the dies are closed up by moving pistons 25 apart, the arms 22, 23 coming into the position shown in FIG. 1. The effect of the traction on the arms 22, 23 is to move the supports 8 and 9 towards one another, i.e., to move together the pairs of sections 4, 5 and 6, 7. During this moving together, the points of flexion 19a of layers 19 come to bear against the object and the pair of sections pivot about the thus formed bearing points so as to close up about the object under the action of the curved plates 11 and 12 which act on each of the sections, as shown at points 12a and 12b for the plate 12 (FIG. 2). This system with three points of action for each pair of die sections ensures closing of the die in a very advantageous manner. At the end ofmovement, the outersurfaces of the die sections come to bear closely against the inner cylindrical surfaces of plates 11 and 12, which ensures that the sections are held accurately concentric. End faces 32 and 33 of of contact.

Thus, during opening of the dies, the die sections automatically move apart from the formed objects, disengaging from the relief formed on the objects and allowing extraction of the formed objects without difficulty.

Generally speaking, the described machine has the following advantages:

easy extraction of the formed objects even when the latter have a relief terminating in the proximity of the joining plane (i.e., plane YY)',

presence of a single exposed joining plane, the other joining plane (vertical looking at FIGS. 1 and2) being concealed by the flexible layer of the dies;

automatic centring of the objects to be formed during I closing of the dies; very tight fit of the objects to be formed in the dies;

automatic opening of the die sections; possibility of rapid removal of the die sections in order to change the dimensions or the engraving.

Of course, it is possible to increase the number of articulated sections joined by a single continuous flexible inner layer over the joining lines between the adjacent sections.

In the described example, the joining plane (YY) of the die may leave two traces on the formed objects along diametrally opposed lines. It is possible to eliminate one of these traces by providing a single continuous flexible layer extending from the face 32 of section 7 to the face 34 of section 5, thus articulating the sections 4 and 6 about their edges 37, 38.Automatic opening can be provided by a device including pins 15 and 16 similar to those described, and with a curved plate analogous to plates 11 and 12 but disposed generally vertically (looking at FIG. 2) and which can be moved outwards or inwards by means of arms articulated on the supports 8 and 9 in a similar manner to arms 22 and The flexible layer l8, 19 not only serves to articulate the die sections together, but also either carries an intaglio or cameo image, or is stuck closely over and transmits a profiled shape on the inner surfaces of the die sections to the objects to be formed.

1 claim:

1. A machine for the forming of metallic objects comprising, a die made of a plurality of pairs of die sections, disposed with the pairs in opposed positions, forming means disposed interiorly of the die sections articulating corresponding die sections for opening and closing of the die by relative opening and closing movement of the paired die sections, said forming means having therein inner surfaces continuous from one of the paired sections to a next adjacent section of a pair effective to shape metallic objects subjected to magnetomotive forming within the die, said forming means having means articulating the individual pairs of sections along next adjacent edges thereof and overlapping said edges, said forming means comprising a layer of flexible material continuous from one die section to another die section of a pair of die sections, and means for actuating the pairs of die sections to an open and a closed position.

2. A machine for the forming of metallic objects according to claim 1, including means inside of the die sections .when closed for effecting magnetomotive forming of metallic objects in the die in conjunction with said forming means.

3. A machine for the forming of metallic objects according to claim 2, in which said pairs of die sections comprises two pairs of die sections, each section having an arcuate configuration, said two pairs being disposed opposed for joining along a plane when closed, each die section being less than a quadrant to allow opening the individual pairs along their articulated edges.

4.-A machine for the forming of metallic objects according to claim 3, including means for each pair of die sections automatically opening a corresponding pair of die sections by pivotal movement along the articulated edges thereof.

5. A machine for the forming of metallic objects according to claim 4, in which the last-mentioned means comprises a spring biasing the individual die section of a corresponding pair toward a direction for effecting pivotal movement at the articulated adjacent edges thereof for opening the pair of die sections, and means guiding each pair of die sections during the opening and closing thereof.

'6. A machine for the forming of metallic objects according to claim 1, in which said forming means inner surfaces comprise an intaglio and/or cameo image thereon.

7. A machine for the forming of metallic objects according to claim 1, in which said means for actuating the pairs of die sections to an open and a closed position comprises means separating one pair of die sections from another pair of die sections along a separation plane to open the die sections and contacting said one pair with said another pair along said plane to close the die sections.

8. A machine for the forming of metallic objects according to claim 7, in whichsaid die sections comprise two pairs of die sections defining each die, one pair of each two pairs being disposed on opposite sides of said plane. 

1. A machine for the forming of metallic objects comprising, a die made of a plurality of pairs of die sections, disposed with the pairs in opposed positions, forming means disposed interiorly of the die sections articulating corresponding die sections for opening and closing of the die by relative opening and closing movement of the paired die sections, said forming means having therein inner surfaces continuous from one of the paired sections to a next adjacent section of a pair effective to shape metallic objects subjected to magnetomotive forming within the die, said forming means having means articulating the individual pairs of sections along next adjacent edges thereof and overlapping said edges, said forming means comprising a layer of flexible material continuous from one die section to another die section of a pair of die sections, and means for actuating the pairs of die sections to an open and a closed position.
 2. A machine for the forming of metallic objects according to claim 1, including means inside of the die sections when closed for effecting magnetomotive forming of metallic objects in the die in conjunction with said forming means.
 3. A machine for the forming of metallic objects according to claim 2, in which said pairs of die sections comprises two pairs of die sections, each section having an arcuate configuration, said two pairs being disposed opposed for joining along a plane when closed, each die section being less than a quadrant to allow opening the individual pairs along their articulated edges.
 4. A machine for the forming of metallic objects according to claim 3, including means for each pair of die sections automatically opening a corresponding pair of die sections by pivotal movement along the articulated edges thereof.
 5. A machine for the forming of metallic objects according to claim 4, in which the last-mentioned means comprises a spring biasing the individual die section of a corresponding pair toward a direction for effecting pivotal movement at the articulAted adjacent edges thereof for opening the pair of die sections, and means guiding each pair of die sections during the opening and closing thereof.
 6. A machine for the forming of metallic objects according to claim 1, in which said forming means inner surfaces comprise an intaglio and/or cameo image thereon.
 7. A machine for the forming of metallic objects according to claim 1, in which said means for actuating the pairs of die sections to an open and a closed position comprises means separating one pair of die sections from another pair of die sections along a separation plane to open the die sections and contacting said one pair with said another pair along said plane to close the die sections.
 8. A machine for the forming of metallic objects according to claim 7, in which said die sections comprise two pairs of die sections defining each die, one pair of each two pairs being disposed on opposite sides of said plane. 